In today's semiconductor manufacturing industry, device speed is of critical importance. Faster and faster integrated circuit and other semiconductor devices are being developed to meet the demands of the various applications for which they will be used and to meet the challenges of device designers who are required to devise faster devices that require faster materials in order to meet the application demands.
Device speed can be increased and optimized by utilizing structures and features formed of materials that are characterized by high electron or hole mobility. Such materials include stressor materials used in conjunction with transistors or other devices. These high mobility stressor materials are advantageously doped with dopant impurities to reduce the resistivity of such structures. This adds to the device speed.
While high-mobility stressor materials provide the advantage of high electron and hole mobility and therefore faster devices, they often include dopant impurity materials that tend to out-diffuse at high temperatures. The sequence of fabrication operations used to form integrated circuit and other semiconductor devices typically includes several such high temperature operations. It can be then appreciated that the use of doped high mobility stressor materials in conventional semiconductor manufacturing fabrication sequences, will cause diffusion of the dopant impurity species from the stressor material and such diffusion can cause shorts or otherwise introduce the dopant impurities into regions where they can adversely affect device performance or completely destroy device functionality.
It would therefore be advantageous and desirable to produce and utilize high mobility stressor materials with suitable dopant impurities in semiconductor devices that are compatible with subsequent high temperature semiconductor fabrication operations, i.e. it would be advantageous and desirable to produce high mobility stressor materials with suitable dopant impurities that do not out-diffuse and adversely affect device performance during subsequent high temperature operations.